phosphines

https://doi.org/10.1351/goldbook.P04553
PH3 and compounds derived from it by substituting one, two or three hydrogen atoms by hydrocarbyl groups R3P. RPH2, R2PH and R3P (RH) are called primary, secondary and tertiary phosphines, respectively. A specific phosphine is preferably named as a substituted phosphane, e.g. CH3PH2 methylphosphane.
See:
phosphanes
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1357 [Terms] [Paper]